Presently, routers and switches with switching capability in the ranges of 50 to 200 gigabit per second are used as the core network routing and switching elements in the backbone of a carrier and the Internet. With the explosive growth of data and Internet traffic, carriers are evaluating a new class of routers and switches that have terabit switching capability in order to satisfy the bandwidth demands from users.
Switches in this new class of terabit switches are very different from current gigabit switches in many aspects such as the number of manageable resources and software scalability, among others. These differences make the monolithic OAM design in current gigabit switches less suited to handle the large amount of network management traffic from operators and Virtual Private Networking (VPN) customers in a terabit switching environment.
For example, in a two terabit switch with 200 network interface cards (NICs), each NIC having 10 Gbits aggregated throughput (e.g., 1 port OC192 or 4 ports OC48 card), the switch could have up to 600 physical ports depending on the configuration of the switch. For a contemporary switch that supports the management of logic interfaces defined in Internet Engineering Task Force (IETF) RFC 2863, the total number of logical and physical interfaces increases substantially to a few thousands. On average, each interface manages a dozen of Management Information Base (MIB) variables, such as the ingress and egress counters of an interface, making the total number of manageable MIB variables for the interface related MIB groups alone to a few hundred thousands. Other MIB groups such as the Open Shortest Path First (OSPF), Multi-Protocol Label Switching (MPLS), and sparing systems all have their own MIB variables, which add to the total number of MIB variables requiring management by the switch's OAM system.
The large number of manageable MIB variables in a terabit switch imposes a scalability challenge on the OAM system. This challenge is increased when many operators try to manage the switch by executing “get” and “set” commands on the MIB variables. Furthermore, envisioned VPN services will allow customers to manage their portion of the switch for Service Level Agreement (SLA) compliance, thereby further increasing the amount of network management traffic in the switch and hence making more demands on its OAM system.
It is unlikely that current monolithic OAM systems will be able to meet the network management traffic requirements of terabit switches as outlined above, and hence a new type of management system for a terabit switch is desired.